"The staggering number — one in eight of all deaths, globally" in 2012 makes air pollution "the single largest environmental health risk in the world today", writes Lucy Westcott (who also writes for The Wire). "The World Health Organization (WHO) says that improved technology used to measure the effects of human exposure to pollutants has led to better estimates of the number of deaths," adds Wescott.
WHO's press release further explains the near-quadrupling over the figure we reported in 2011 that was restricted to data from "1,100 cities across 91 countries, including capital cities and cities with more than 100,00 residents based on measurements from 2003 to 2010."
The new estimates are not only based on more knowledge about the diseases caused by air pollution, but also upon better assessment of human exposure to air pollutants through the use of improved measurements and technology. This has enabled scientists to make a more detailed analysis of health risks from a wider demographic spread that now includes rural as well as urban areas."
However, deadly air pollution is not restricted to the smog and particulate pollution that envelop cities. WHO notes that 61% of air pollution-caused mortality (4.3 million deaths) in 2012 was attributed to "indoor air pollution in households that cooked over coal, wood and biomass stoves," writes Wescott.
The effects of air pollution transcend public health and mortality. Bloomberg News reports that "(a)ir pollution led to genetic changes that may have sapped learning skills in children whose mothers were exposed to a Chinese coal-fired power plant before it was shuttered a decade ago."